Professor Kelman received his Ph.D. at Yale University, where he worked with Carl Hovland in the early days of the Yale attitude change project. He first came to Harvard in 1957 as Lecturer on Social Psychology in the Social Relations Department. In 1962 he moved to the University of Michigan as Professor of Psychology and Research Psychologist in the Center for Research on Conflict Resolution. He was an active participant in and for a while chair of the Joint Doctoral Program in Social Psychology. In 1968 he returned to Harvard as Richard Clarke Cabot Professor of Social Ethics, a chair originally held by Gordon Allport. From 1994-97, he chaired Harvard's Doctoral Program in Social Psychology. In 1999, he retired from teaching, but continued as Richard Clarke Cabot Research Professor of Social Ethics. In 2004, he became Richard Clarke Cabot Professor of Social Ethics, Emeritus.

The theoretical focus of Professor Kelman's work throughout his career has been social influence and attitude change, with an emphasis on the distinction between different processes of influence; on the relationship of action to attitude change; and on conceptions of personal responsibility for actions ordered by legitimate authorities. The last of these topics is the subject of his book, Crimes of Obedience: Toward a Social Psychology of Authority and Responsibility, coauthored with V. Lee Hamilton (1989). He has explored influence processes in various applied settings, including psychotherapy, international educational exchanges, and more recently, problem-solving workshops in the resolution of international conflicts.

The latter work bridges his work on social influence and attitude change with his other long-standing interest in the social psychology of international relations. His work in conflict resolution has concentrated for a number of years on an action research program on the Arab-Israeli conflict. He has developed interactive problem solving, an unofficial third-party approach to the resolution of international and ethnic conflicts, anchored in social-psychological principles, and he and his colleagues have applied this approach to the Israeli-Palestinian conflict and to other protracted conflicts between identity groups. He is associated with Harvard's Weatherhead Center for International Affairs, where he directed the Program on International Conflict Analysis and Resolution (PICAR) between 1993 and 2003 and co-chairs the Middle East Seminar.

Professor Kelman has also written and lectured extensively on the ethics of social research and social intervention, including ethical problems in human experimentation and the social consequences of psychological and social research.